How to install Docker on 32bit machine having Ubuntu 12.04?
Although this is an old queston i found a simple solution for current (18.0.3) releases of docker-ce: https://github.com/mforkel/docker-ce-i386
The description of README-i386.md is all you need, but here the shot description:
1) use git clone to get a local version of the repository
2) in my case i needed a debian .deb file so i ran ARCH=i386 DOCKER_BUILD_PKGS=debian-stretch make deb in the main Folder
3) when the makescript finished you can find your deb file in ./components/packaging/deb/debbuild/debian-stretch
I did not test this build extensively, but running docker run hello-world worked without errors
EDIT: By now i can confirm many packages working. E.g. Portainer and Nextcloud. Some packages are build agains 64bit architecture and you have to build the container on your own, but it worked for me without any problems
As per the prerequisites:
Docker requires a 64-bit installation regardless of your Ubuntu version. Additionally, your kernel must be 3.10 at minimum. The latest 3.10 minor version or a newer maintained version are also acceptable.
You will not be able to install Docker onto a 32bit platform.
UPDATE:
It is possible. See answer from MS Berends in this same thread
This is possible these days, with just a simple script. You could use https://gitlab.com/docker-32bit/ubuntu.
Works perfectly on my Ubuntu 16.04 32-bit system. I used it to install the office server Collabora Online for my Nextcloud:
wget https://gitlab.com/docker-32bit/ubuntu/raw/master/build-image.sh
# for Debian, use one of:
# wget https://gitlab.com/docker-32bit/debian/raw/armhf/build-image.sh
# wget https://gitlab.com/docker-32bit/debian/raw/i386/build-image.sh
sudo bash build-image.sh
docker -v
# Docker version 1.13.1, build 092cba3
sudo docker pull collabora/code
sudo docker run -t -d -p 127.0.0.1:9980:9980 -e 'domain=my\\.domain\\.com' --restart always --cap-add MKNOD collabora/code
Update December 2020
It seems that sudo apt install -y docker.io might just work on Debian 10 Buster and would install a 32-bit compatible Docker version. Didn't test it myself, but John Smith confirmed this.
there has been some hacking, unsupported ways to do so, see
http://mwhiteley.com/linux-containers/2013/08/31/docker-on-i386.html
Keep in mind that the previous link was in August 2013, I am not sure you will be able to do the same with the latest versions of docker.